good birding

GOOD BIRDING

The sea ducks of Isle au Haut, and why harlequin ducks have so many broken bones

For the second year in a row, the Island Heritage Trust organized a chance to experience the variety of sea ducks, like the Harlequin duck pictured here, that can be found in the archipelago around Stonington.

By Bob Duchesne, Special to the BDN

Posted April 04, 2014, at 5:25 a.m.

The date was March 29. The forecast for the annual Isle au Haut duck tour called for shifting winds and four-foot swells. I was prepared for a rough trip, yet the ride was much worse than I expected. We pitched and rolled. We tossed violently from side to side.

On the other hand, this year’s boat ride on the Isle au Haut Ferry went smoothly. For the second year in a row, the Island Heritage Trust organized a chance to experience the variety of sea ducks that can be found in the archipelago around Stonington.

Harlequin ducks are the starring attraction. For decades, these “Lords and Ladies of the Surf” have collected along the southern side of Isle au Haut. It is the largest concentration of these colorful ducks in eastern North America. During the early years of my involvement with Maine Audubon, the Penobscot Valley Chapter often organized boat trips to see them. Since the 1980s, the ducks have become more common along the mainland, and the annual trips ceased. I was delighted when the Island Heritage Trust revived the tradition, not just because the harlequins are extraordinarily appealing, but because they keep good company. There are a lot of other sea ducks worth watching out there.

Harlequin ducks breed in the raging whitewater of Canadian streams. On their wintering grounds in Maine, they forage in the turbulent surf zone where no other duck dares to go. The harlequins take advantage of this rich food supply, but at a cost. Harlequins suffer more broken bones than any other species. X-rays reveal that most harlequins have healed fractures. Apparently, they mend quickly.

We were not disappointed. All along the exposed southern edge of the island, small groups of harlequins bobbed in the white froth of the pounding surf. Officially, we tallied 87, but doubtless many more lurked in the foam along the seawall. Winds were light, but rollers leftover from a passing storm were throwing waves at us. Rather than circle the island, we decided to return home via the lee side in order to look for other species.

Passengers are continually surprised to find out how many common loons winter offshore. We passed dozens. We enjoyed flocks of surf scoters in the distance and got closer views of a few white-winged scoters. Red-breasted mergansers and long-tailed ducks were in good supply. Black guillemots are always plentiful in these waters.

Red-necked and horned grebes popped up in the sheltered coves. Buffleheads also confined themselves to calmer waters, mostly in the Thoroughfare next to Isle au Haut harbor. Our group picked out a few common goldeneyes there, too.

We witnessed hundreds of common eiders, but that’s a worrisome number. There used to be thousands. Eiders have declined precipitously along the Maine coast over the last ten years. Surveys show that most of them have moved south to Massachusetts. Current explanations are speculative. Predation may play a small role. Eagles take eiders and great black-backed gulls devour 90 percent of the chicks. But there is a greater concern that green crabs — an invasive species — are wiping out our mussel beds, the favorite food for eiders. In any case, those of us who took this boat ride in the 80s remember far more diving ducks than are currently present.

Second only to the harlequin ducks, purple sandpipers were the crowd pleasers this year. Captain Garrett Aldrich nosed the boat in close to several flocks as they huddled on the shoals. Purple sandpipers are common along Maine’s rocky coast in winter, but it takes a knack to spot them. Their purplish-gray color matches the hue of wet granite and the sandpipers are all but invisible when roosting at the waterline. Experienced birders look for little “bumps on the rocks” wherever there are exposed ledges. We found bunches.

I’ll be on the Isle au Haut Ferry a lot this year. You’re invited, too. They are a big part of the Wings, Waves, Woods birding festival in Stonington over the third weekend of May, and the boat has scheduled five trips to see the puffins on Seal Island later in summer. It’s a large, stable, comfortable boat, which is suitable for any offshore adventure. For information, visit isleauhautferry.com. Just nudge me aside if I am blocking your view.